


The Smell of Him

by halcyon1993



Series: The Kinky Adventures of a Wolf and His Boy [40]
Category: Teen Wolf (TV)
Genre: Alternate Universe - Human, Anal Fingering, Anal Sex, Barebacking, Bottom Derek Hale, Cock Slut Derek Hale, Comeplay, First Meetings, Hairy Derek Hale, Large Cock, M/M, Mutual Masturbation, Nipple Play, Oral Sex, Pining Derek Hale, Plot What Plot/Porn Without Plot, Resolved Sexual Tension, Rimming, Roommates, Scent Kink, Stiles Stilinski Has a Big Dick, Top Stiles Stilinski, Voyeurism
Language: English
Status: Completed
Published: 2018-10-19
Updated: 2018-10-19
Packaged: 2019-08-04 12:44:27
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,378
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16346972
Author URL: https://archiveofourown.org/users/halcyon1993/pseuds/halcyon1993
Summary: Shortly after he gets a new roommate in the very attractive Stiles Stilinski, Derek develops a fetish when he happens upon a pair of Stiles’ come-stained boxers. What happens when he accidentally steals them and Stiles finds out?





	The Smell of Him

**Author's Note:**

  * For [77thdegree](https://archiveofourown.org/users/77thdegree/gifts).



> As always with this series, don't judge me for the depravity I have written…

Derek is screwed.

He leans back against the counter in the little kitchen of his apartment and drinks from a cup of black coffee as his new roommate, Stiles, exits the bathroom in nothing but a towel. The younger man's pale, mole-dotted skin is practically luminescent covered in water droplets. Derek can't help but stare as Stiles says good morning to him and turns to walk down the hall toward his bedroom, the thin fabric of his towel clinging to the shapely globes of his ass. Derek wishes that Stiles would lose his grip and the towel would flutter to the floor, allowing him to see bare flesh.

Yeah, Derek is so fucking screwed.

As he takes another sip from his mug, he ruminates on how he got to this point.

His previous roommate was the devil. He was messy, smelly and loud, and it took far too long to get rid of him. Afterward, Derek could have afforded to pay the rent by himself, no problem, but he doesn't like living alone and likes the extra income that having a roommate grants him. So, as soon as he'd finished cleaning up all the mess the other guy had so graciously left for him, Derek put up an ad online looking for someone else. He'd been very specific about wanting the antithesis of his old roommate, and he'd somehow got it.

Unfortunately, Stiles came with other problems.

When he'd stopped by so that he could check the place out and Derek could gauge how well they'd get along, Derek had been wonderstruck.

His first thought was that Stiles was gorgeous. There was no other word for it, with his pretty cinnamon-coloured eyes alight with happiness and his plump lips twisted into a friendly smile. Derek thinks he probably came off as a complete idiot before he managed to get his act together and let Stiles in, but the interview had thankfully gone well after that and Stiles moved in the next day.

Now, it's a week later and Derek is regretting his rashness. He finds himself intensely attracted to his new roommate in a way he has never been attracted to anyone before. It's inexorable, and he knows he's going to end up doing something to mess it up and make Stiles leave.

And that would be awful.

In the short time he has lived with Derek, Stiles has proved himself to be a very good roommate. He is conscientious, tidy, quiet, can cook well, and he doesn't leave his dirty laundry all over the place or dishes piled up in the sink. The fact that, if he left, Derek wouldn't have anyone to stare at like a lovesick teenager anymore is beside the point. It really is.

Derek would swear on it.

A few minutes later, Stiles emerges from his bedroom dressed in a red flannel shirt and a pair of black chinos that hug his coltish legs. "Hey," he greets.

"Hey," Derek echoes, stepping aside to maintain some distance between them. If Stiles got too close, any control Derek has mustered might just vanish in an instant.

The younger man frowns slightly. "Are you okay? You're acting weird this morning."

"Yeah, I'm fine," Derek lies. "Just, uh, didn't get much sleep last night."

"Hence the coffee?"

"Hence the coffee."

Stiles keeps appraising him for a few moments, his eyes narrowed like he's on to Derek's lie, but then he smiles affably. "Alright then. I hope you sleep better tonight."

"Thanks."

After he has grabbed himself an apple from the fruit bowl on the counter, Stiles bids Derek goodbye and exits the apartment to go to work. Derek is both glad and disappointed to be left alone again. He wants Stiles to come back, but at the same time, it's undoubtedly better for both of them if he doesn't. Derek doesn't like being at war with himself like this, but, as he downs the last of his coffee, he can't see things changing anytime soon.

He'll just have to learn to live with it.

* * *

Once he has washed the long workday from his body, Derek climbs into bed that night in a pair of red boxer-briefs and tries to get some sleep. He spent most of the day dealing with asshole coworkers and a boss that never takes his side, and now he wants nothing more than to get through the rest of the week so that he can recuperate over the weekend. He lies on his back with one hand tucked behind his head and the other resting on his bare stomach, and he has just got close to drifting off when he hears a noise from elsewhere in the apartment.

Opening his eyes, Derek stares at the ceiling and attempts to figure out what it is, but the answer doesn't come to him right away. Something about it is definitely familiar, but it's too muffled for him to discern why. But then the noise gets louder and his eyes widen when he finally identifies it.

It's a moan.

And it came from Stiles' bedroom. In Stiles' voice.

Derek doesn't think Stiles had anyone over when he went to bed, so that must mean that his roommate is jerking off. His cock goes from soft to rock-hard in the space of a single second. Before he can think better of it, Derek shoves his underwear down his legs so that they get lost in the sheets now pooled at the foot of his bed and then wraps his hand around his erection. He breathes slowly and deeply, creating as little noise as possible so that he doesn't miss anything coming from across the hall. For him to be able to hear Stiles, the younger man mustn't be trying as hard as he is to stay quiet, which has dirty fantasies floating through Derek's head.

He imagines that Stiles is doing this deliberately, that he is sitting back against the headboard of his own bed, his eyes on his closed door as he strokes himself and moans just loud enough for Derek to hear him. The reality is probably nothing like that. From getting to know each other a bit this past week, Derek is aware that Stiles lived alone in his old place, so he probably just isn't used to having to be quiet when he pleasures himself.

Derek is glad, because those moans…

He has never heard anything more erotic.

As he moves his hand over his cock, using pre-come to slick the way, Derek pushes away the reality and goes back to his fantasy. He closes his eyes again and pinches his left nipple with his free hand as more of Stiles' moans reach his ears. Behind his eyelids, he envisages what had been concealed beneath Stiles' towel that morning. He almost moans himself as he imagines how big he'd like Stiles' cock to be—long enough to be intimidating, and thick enough to stretch him just shy of the point of pain. Derek's hole clenches as he pictures Stiles slicking up his massive dick and then sliding it inside his roommate's—no, his _lover's_ —willing body.

Derek isn't a stranger to bottoming. He likes it well enough, but something tells him that, were Stiles the one fucking him, he would become insensible with pleasure. He jerks his cock faster, swiping his index finger over the slit on each upstroke. When the noises stop for a few seconds, Derek worries that he has missed the climax, but then Stiles moans again for a final time. It's pitched higher and tapers off into a sharp whine that's so hot that it sets Derek off as well. He shoots like a rocket, painting his torso with his own release.

When it's over, Derek basks in the afterglow and then grabs some tissues from his nightstand. He cleans himself up before turning over onto his side to finally get some sleep. Worn out and sated, it comes easily.

* * *

The next morning, Derek pulls on some grey sweatpants and a white tank top and exits his bedroom. Stiles comes out of his at the same time, already dressed and ready for the day. Derek can barely look him in the eye after last night, but if Stiles notices that he's acting off, he doesn't mention it. He just gives Derek his usual chipper morning hello and walks into the kitchen.

Derek goes to follow him, but then he spots that Stiles has left his bedroom door open. Since the younger man moved in, he has kept the door closed at all times, which Derek didn't mind—Stiles is entitled to his privacy, after all. Because of this, Derek doesn't think anyone could really blame him for being overcome by curiosity. He's sure that he could just ask Stiles and Stiles would have no problem with it, but he doesn't ask. His crush must really be getting out of hand if it's got to the point where he is resorting to sneaking into Stiles' room to learn more about him, but Derek is already inside now, so he figures it's too late to back out.

He surveys all the changes that Stiles has made to the place.

He saw the bedroom while it was his old roommate's, and the difference is stark. Derek's old roommate had kept the place a total pigsty, with old pizza boxes and takeout containers on nearly every surface, clothes all over the floor and different skin mags always out on his nightstand. With Stiles living there, it looks lived-in but still clean, showing Derek that the way Stiles has cleaned up after himself elsewhere in the apartment isn't just him trying to look good; it's genuinely the way he is.

The floor is clear of detritus.

There are books stacked on top of the dresser, spilling over from the bookcase to the left of the door, which lets Derek know that Stiles is quite the bibliophile.

On the walls, Stiles has stuck up a few posters of bands that Derek hasn't heard of and superhero movies he _has_ heard of but hasn't seen.

Even the bed is made, the sheets tucked in and mostly wrinkle-free.

The only thing that looks out of place in the room is some sort of fabric sticking out from beneath the mattress, like Stiles had tried to hide it but did a poor job of it.

His curiosity ramping up, Derek approaches the bed and tugs on the fabric to pull it out. When he has it in his hand, he stands at his full height and inspects it. His breath hitches and his cock starts to swell in his sweatpants. The fabric turns out to be a pair of Stiles' boxers, and the black material is encrusted with patches of white. Derek doesn't even have to think about it to deduce what the stains are from: come.

He has found what is essentially Stiles' come rag.

And for some reason, he hasn't dropped it to the floor in disgust yet. In fact, his cock only gets harder.

Why?

It should be gross. From the amount of stains on the boxers, there must be dozens of loads dried on them, maybe more. Derek doesn't know how old the boxers are and when the last time they were washed was. For all he knows, they're years old and they've _never_ been washed. Derek spends what is probably too long standing beside Stiles' bed, just staring at the boxers in his hand. He can't seem to tear his eyes from them, can't stop wondering if Stiles used them last night when he came.

He must have. Right?

"Derek? D'you want some coffee?" Stiles calls to him from the kitchen.

Startling, Derek hightails it out of the room. He retreats across the hall before Stiles can see his hard-on and shouts, "Yeah, coffee'd be great!" back over his shoulder.

It isn't until he's back in his own bedroom with the door shut safely behind him that he notices he still has Stiles' come-stained boxers in his hand. _Fuck_. Maybe he can sneak them back into their hiding place before Stiles finds out that they're gone. He presses an ear to his door and listens to see if his roommate is coming back, and when he hears nothing, he puts the hand not still clutching the boxers on the door handle, intent on making a mad dash for it.

But as soon as he has his door open a crack, footsteps sound in the hallway.

Stiles tells him that his coffee is on the side waiting for him, then Derek winces when he hears the sound of Stiles closing his door. Damn. It's too late. All Derek can do now is pray that Stiles doesn't check that his come rag is still there. Why would he? He has to leave for work in a few minutes, and that isn't enough time to jerk off again, right? Derek should be safe.

He feels like he is talking himself down from a ledge, but it works, his heartbeat slowly returning to its resting pace. When he has calmed, Derek stuffs Stiles' boxers beneath his pillow so that he can put them back later. For the past week he has got home half an hour before Stiles, so he should have enough time. That done, he tells his dick to behave and leaves his bedroom again, doing his best to pretend that nothing out of the ordinary is going on, even though he doesn't currently have an audience to perform for. It just feels like the right thing to do, and there is no use panicking now.

* * *

When Derek gets home that afternoon, he heads straight to his bedroom. He pulls off his tie on the way, and when he's inside he tosses it and his suit jacket onto the end of his bed before all but collapsing next to them on his back. God, what a day. It was much more pleasant than the one before it, with his coworkers minding their own business and his boss actually in a good mood for once, but it was still intolerably long. And for one reason:

Derek couldn't stop thinking about what was beneath his pillow.

Now, he turns his head to the side and tentatively reaches across the sheets to stick his hand beneath the pillow until his fingers come into contact with Stiles' boxers. He should put them back while Stiles is still out. That was the plan that morning. So why isn't he getting up and following through? Something stops him. Derek swallows tightly and pulls the boxers out so that he can look at them again. Like earlier, just the sight of them has him getting hard. He drops the boxers for a moment and doesn't take his eyes off of them as he gets out of the rest of his clothes.

When he's naked, Derek takes Stiles' boxers back in hand and brings them closer while he leisurely strokes himself. He still has around twenty-five minutes until his roommate gets back, so, even though he shouldn't, Derek indulges himself. He doesn't think he'll have this opportunity ever again, so he doesn't allow logic and reason a place in his brain.

He simply chases his arousal like an animal.

As he keeps jerking off, Derek holds Stiles' boxers up with his other hand and fingers the stains. Why is this so hot? Derek enjoys swallowing every now and then, but this? Maybe he's only turned on because it's something most people would find gross. It's the taboo of it. After a while, he turns the boxers around in his hand to look at the stains on the other side, but his fingers get tangled in the fabric and he accidentally drops them. Right on his face. Out of shock, Derek breathes in sharply through his nose and then goes tense all over.

Taking his newfound kink even further, Derek thinks the boxers smell so fucking _good_. Afraid it was just a fluke, he makes himself relax and takes another slow breath, just waiting for his stomach to revolt.

But it doesn't.

All that happens is his dick twitches in his loose grip and a bead of pre-come dribbles down the shaft. It wasn't a fluke—he really does enjoy the pungent, almost meaty smell of Stiles' come-stained boxers. It takes a few seconds for him to get on board with this revelation, but once he is, he runs with it. He resumes jacking off and with his other hand he rubs the boxers around his face, taking long, gasping breaths and moaning like a whore.

Eventually, Derek feels something wet smear up his cheek and pauses to investigate. He finds a damp patch on the left side of the boxers that he hadn't spotted before, and right away he knows that it's the remnants of Stiles' load from when he masturbated last night. The perimeter of the patch is already dry, but the inside is still sticky and slightly clumpy. The boxers being hidden beneath Stiles' mattress and then being balled up under Derek's pillow must have prevented the come from drying up entirely. It's with drool leaking from the corner of his mouth that Derek abandons all reason and stuffs the sticky patch into his mouth. He sucks on it just once, and as soon as he gets a taste of Stiles' latest release, he orgasms untouched.

In a mirror of the previous night, he lies on his bed covered in his own seed while he recovers, but this time, instead of using a tissue from his nightstand, Derek feels naughty as he uses Stiles' boxers to clean himself up. He figures that his roommate won't be able to tell the difference, so he should be able to get away with it. When he's as clean as he can be without taking a shower, Derek slips on some basketball shorts he still owns from when he played back in high school and walks across the hall to put Stiles' boxers back where they belong.

As he walks back into his own room, he doesn't notice Stiles peeking around the corner at the end of the hall, a smirk stretching his lips.

* * *

The very next day, a Saturday, Stiles bides his time. He lets Derek keep pretending that everything is normal, all while he makes the occasional comment that sounds innocent on the surface but has a dirty meaning if you look hard enough. By the evening, Stiles can tell that he's getting to Derek. The bearded man squirms deliciously with each comment, and when they're watching some bad comedy together on the sofa after dinner, in his periphery he sees Derek cross his legs to hide his erection.

When Derek eventually makes his escape to his bedroom, Stiles has also managed to work himself up so much that he doesn't think he can wait any longer. He takes a quick detour into his own room to get his boxers from where Derek had put them back beneath his mattress, and then he knocks on Derek's door. When he is given permission to enter, he hides his boxers behind his back and walks inside. He finds his roommate sitting on his bed with a book open in his lap, an obvious attempt to cover the erection he still hasn't managed to get under control.

Poor Derek Junior.

"What's up?" Derek asks him. His voice sounds fine, but there is tension around his eyes.

Stiles steps further into the room and pushes the door to. "I wanted to talk to you about something, if you've got a minute."

"Sure."

Dropping the pretence, Stiles brings his hand around from behind is back. "It's about these."

Derek's face drains of colour and his book falls off of his lap and onto the bedsheets, revealing the tent in his jeans.

"Derek?" Stiles calls. "Did I break you?"

"W-what are those?"

_Ah, so he's still going to pretend._

"It's okay, dude," Stiles reassures. "You don't have to lie to me. I know you found them before. I saw what you did with them yesterday."

If at all possible, Derek's face gets even paler. "You did?"

"Yup. And before you freak out, I'm not mad."

"Y-you're not?"

"Nope. Wanna know why?"

Derek nods slowly and some of his fear fades.

"Because I thought it was hot as hell. Almost as hot as you are."

Derek looks down as the colour returns to his face and then some. His cheeks and the tips of his ears pink up adorably. "You did?"

"I did…and if you'd be okay with it—and at the risk of making things awkward around here—I'd like us to stop dancing around each other now and admit that we want each other. Deal?"

Derek looks up from beneath his eyelashes like he's double-checking that Stiles is being serious, so Stiles makes his expression as earnest and open as he can. Thankfully, this seems to be enough, because Derek puts his book on his nightstand and tilts his face back up, giving Stiles the perfect opportunity to find out if Derek's lips are really as soft as they look.

Spoiler alert: they are.

* * *

The kiss is fiery right off the bat. Both of them battle for dominance, and Derek is impressed when Stiles doesn't back down at all. Because of how he looks, he is used to other guys thinking he'll always be the one in charge. Sometimes that's fine, but right now he has no issue at all letting Stiles have the control. He actually _wants_ things to play out that way, so he gives in and is soon lying on his back with Stiles above him, kissing him so well that he can't help but whimper into Stiles' mouth. He would be embarrassed about making such a sound, but from the way Stiles grinds his erection against him, he can tell that the younger man likes it.

When the kiss ends, Derek looks up at Stiles and sees that his pupils nearly eclipse his irises, his lips are red and slightly swollen, his hair is dishevelled from Derek running his fingers through it, and his cheeks are ruddy with arousal. To Derek, Stiles is the most gorgeous thing he has ever seen, and he can't resist giving his plump mouth one final peck.

Afterward, Stiles sits up so that he is kneeling between Derek's thighs. "Here, I know you want these," he says, dropping his boxers onto Derek's chest.

"You really don't mind?" Derek asks him, just to make sure.

"Do I care that you're apparently a kinky son-of-a-bitch? Hell no. I feel like I've hit the jackpot, dude."

"Don't call me 'dude'."

"Would you prefer I call you 'come-slut', then?"

Derek glares and shakes his head, even though he supposes it would be accurate.

Stiles chuckles. "Whatever. You can do whatever kinky shit with those that you want."

"And what're you gonna do?"

Stiles just grins.

Before Derek can say anything else, Stiles pulls him up, yanks off his shirt and then strokes his hands over every inch of tanned skin he can reach. Stiles bites his bottom lip and makes a sound of approval as he runs his fingers through Derek's chest hair and then plucks at his pebbled nipples, making Derek groan, and then he traces the contours of his abs.

"What's your workout routine? 'Cause… _damn_."

Through the pleasure, Derek manages to reply with, "You're welcome to come along the next time I go to the gym."

"We'll see. The thought of seeing you get all hot and sweaty _is_ appealing."

Derek thrusts his chest out when Stiles returns his attention to his nipples and plays leisurely with them, sending shockwaves straight to his aching cock. His confidence grows enough for him to say, "There's nothing stopping us from getting sweaty right now."

"True."

Stiles gives Derek's nipples a final twist before moving his hands to Derek's jeans. He undoes them and tugs them and the blue boxer-briefs beneath down his muscular legs, leaving him nude. Derek's seven-inch cock smacks against his hair-dusted abs when it's freed, pre-come already collecting at the slit. He bucks his hips when Stiles wraps a hand around him and gives him a few strokes, his head cocked to the side as his countenance fills with desire and admiration. His grip tightening slightly is all the warning Derek has before Stiles descends on him, taking him all the way inside his mouth in one fell swoop. Derek chokes on a groan as wet heat surrounds him and Stiles starts bobbing his head, his tongue swiping over the slit to taste his pre-come.

Stiles pulls off long enough to rasp, "You taste good," before sucking Derek right back in, sinking down until his nose is buried in the dark curls at the base. For his part, Derek fists one hand in Stile's hair and, thinking back to the permission he was given to let out his inner freak, he brings Stiles' come-stained boxers up to his face and sniffs them. The smell is slightly different from before, likely because the fabric now has his own come on it as well, but Derek vehemently enjoys it regardless.

"You're filthy," Stiles comments, letting Derek's cock slip from his lips with a pop.

"You said I could," Derek reminds him, almost hiding behind the boxers.

"I did. You're filthy, and I love every bit of it."

"Good."

The next thing Derek knows, Stiles uses a surprising amount of strength to flip him over onto his front and stuffs a pillow beneath his hips to raise his ass up. There is no way to misconstrue what Stiles is planning to happen next. Derek gets over the shock of his new position quickly and arches his back to push his ass out even more, hardly able to believe that he is going to see if the reality lives up to the fantasy he'd had yesterday evening, if Stiles' cock will stretch him wide like it had in his head. He's already desperate for it.

Derek feels Stiles palm his cheeks and relishes the compliments he receives. Stiles tells him that he loves that Derek is hairy here too, and he calls his hole pretty. No one's said something like that to him before, but he discovers when his chest warms that he really likes it.

He gasps when Stiles parts his hairy cheeks and licks enthusiastically over his entrance. He is quickly learning that, when his roommate does something, he gives it his all. He'd done it with the blowjob, brief though it was, and he does it while eating Derek out like he is a starving man and Derek's ass is an all-you-can-eat buffet. Derek has never felt so wanted. It's like Stiles will die if he doesn't have him then and there.

When Stiles wiggles the tip of his tongue inside, Derek sticks his face in Stiles' dirty boxers and bites them to muffle the noise that wants to come out. It still sounds loud in the bedroom, bouncing off the walls. It spurs Stiles to work his tongue harder into Derek's body.

All Derek can do is pull at his own hair and slowly undulate his hips, alternating between grinding his cock into the pillow beneath him and pushing his ass back onto Stiles' face. The pleasure builds, the hairs on Derek's arms standing on end as he approaches orgasm. Right before it hits, Stiles seals his lips around his hole and sucks, which is the thing that sets Derek off. With a broken sob, he soaks the pillow and his own stomach with his release, the movement of his hips getting wilder until the pleasure moves into pain and he is too sensitive to move anymore.

He goes boneless, Stiles' boxers falling from his mouth as he drops his head and presses his cheek to them instead.

He blinks tiredly as he regains his breath and Stiles' mouth leaves his ass, but Stiles' touch isn't gone for long. Just a few seconds later, Derek feels a slender finger slide into his body. The glide is so smooth and easy that it can't just be aided by spit. When he acquires enough energy to turn his head to look, he sees that the top drawer of his nightstand is open, meaning that Stiles had found his half-used tube of lube while he was recovering.

"I hope you don't mind," Stiles says from behind him, sliding his finger in and out.

"Not at all…" Derek replies. He gasps when Stiles brushes his finger over his prostate. He's still too sensitive from his orgasm for it to be truly pleasurable, but he doesn't ask his roommate to stop.

"I can't wait to get inside you," Stiles murmurs. He leans over Derek and kisses over his shoulder blades.

"Yeah?"

"Mmhmm. I swear you've been teasing me with this ass of yours. The way your jeans always cup it so perfectly, it's like they were designed to drive me crazy."

"Maybe they were," Derek jokes.

Stiles keeps talking: "You have no idea the things I've wanted to do to you ever since I met you. I've seen you coming back from the gym all sexy and sweaty. I wanted to lick you from head to toe, to lick the sweat from every inch of your body and then push you down on whoever's bed was closest and have my way with you. And I'm finally getting my wish, aren't I? I'm gonna fuck your ass so hard you'll never forget the feeling of my cock inside you."

Derek shivers and moans his approval.

"You like that idea, huh? You like that I'm gonna stick my cock in your greedy hole in a minute?"

"Uh-huh."

"You—a big manly man—are really a big slut for cock, aren't you?"

"Y-yeah…I love it."

"I bet you do."

Stiles inserts a second finger and thrusts them with more purpose. He goes back and forth between stretching Derek out and just rubbing circles over his prostate, until Derek feels like he's going out of his mind. His cock is rapidly getting back with the programme. It seems far too soon for him to get hard again, but it's like Stiles is beating him into submission with his fingers, until his cock has no choice but to fill with blood once more.

When two fingers become three and then Stiles eases his pinky inside his body as well, Derek can't take it anymore. "Okay, that's enough! Just give to me already!"

"Someone's cranky," Stiles teases him.

"You would be too if someone fingered you for this long."

"You can pay me back next time."

With that promise, Stiles mercifully withdraws his fingers, and then Derek hears him slicking himself up. A moment later, Stiles plants his left hand next to Derek's head and uses the right to aim the tip of his cock at Derek's prepped hole. Derek definitely feels like a slut as he makes a needy noise in the back of his throat and lifts his hips so that Stiles' cock nudges his hole like a kiss.

"Be patient," Stiles whispers into the shell of Derek's ear.

"You're such an asshole," the bearded man complains, wrapping his hand around Stiles' wrist.

"And proud of it."

Before Derek can complain again, Stiles finally starts the long process of entering Derek's body. Derek's eyes go wide when the head pops past the first ring of muscle and he feels just how big Stiles actually is. He definitely lives up to his fantasy. In fact, Derek thinks Stiles might actually be _bigger_ than he'd imagined him, and he couldn't be gladder, even when the burn is intense as Stiles works the next few inches inside. By the time Stiles' hips meet Derek's cheeks, Derek has lost count of how many inches he has taken, and all he can do is pant into Stiles' boxers as he gets used to being filled to the brim like this. He's sure he'd burst if he had to take even one more millimetre.

"You okay?" Stiles asks him, resting his weight atop him.

Derek nods and is comforted by said weight. "Y-yeah…s'just a lot, y'know?"

"Oh, I know."

Stiles sounds intolerably smug, but Derek supposes he has a right to be when he has shoved what feels like an entire baseball bat up his ass.

For several minutes they both lie there, Derek pressed into the mattress by his new lover. While he waits patiently, Stiles resumes peppering Derek's shoulders and neck with kisses, helping him to relax and acclimate to his huge cock. Derek turns his head and meets Stiles' lips, and they share a kiss that's very different from their first. While that one was filled with passion and pent-up sexual frustration, this kiss is made up of affection and softness. Derek likes them both, but something about this one makes things so much more intimate.

"Okay," he says eventually, as Stiles nuzzles into the side of his neck. "I think I'm ready now."

"Good. Tell me if you want me to stop, okay?"

"I will."

When Stiles pulls out most of the way and then slowly thrusts back inside, Derek chokes on his own breath and doesn't know how it could possibly get better. But then, with the second thrust, Stiles hits his prostate dead-on and Derek gets his answer. Fireworks go off behind his eyelids and his mouth hangs open as pleasure the likes of which he has never known courses through him.

Each thrust gets more and more toe-curling, until Stiles speeds up and gives Derek's hole the pounding it has always craved. Derek soon finds a rhythm with him, shoving his ass back at the same time Stiles thrusts forward so that their skin slaps together and the thrusts feel like they have even more power behind them. Derek likes tender sex, but for him, nothing is quite like the rough, ball-slapping intensity of what Stiles is giving him now. Each time Stiles fucks all the way inside, it's like Derek can feel Stiles' cock in his throat and that's what he's really choking on.

"God, you feel so fucking good!" Stiles cries above him.

"R-right— Right back at'cha," Derek responds.

"Such a tight ass."

 _Not for long,_ Derek thinks. He can't wait to see how long the discomfort lasts after this. He bets he won't be able to sit properly for days.

"I'm not gonna last," Stiles tells him after a couple minutes, his thrusts becoming jerky and less coordinated. "You're just so _tight_."

Sure enough, another few thrusts later, Stiles sinks inside one last time and then stays there, all of his weight falling back onto Derek as he grinds his hips against Derek's cheeks and shoots deep in his guts, painting his insides with his come. Derek just lies there and takes it. The dirty part of him is pleased that he made Stiles orgasm so quickly, and he can't help but think that Stiles coming bare inside him like this is a possessive act, like the younger man is claiming him as his.

It's probably not very PC, but Derek couldn't give less of a damn.

When Stiles' orgasm ends and he picks himself up off of Derek, his cock slips out of Derek's hole with a torrent of come.

"Wow, I really destroyed you," he says.

"Wish I could see," Derek breathes, already picturing it.

"Hang on a sec."

Derek jumps when he hears a shutter click, and then Stiles' phone is in front of his face with a photograph on the screen. Derek is in awe of how he looks. His hole is red and puffy, and so loose that he can actually see up inside of himself, can see how his pink walls are slathered in white fluid, some of which drips out of him and runs down his perineum.

"You really did," Derek concurs. He's too amazed to be mad that Stiles took a picture of him without his consent.

"I'm keeping that, by the way," Stiles tells him, his tone brooking no argument.

"Fine by me."

"Cool. Now let's get you taken care of, shall we?"

At Stiles' instruction, Derek turns back over and hands over the soiled boxers. Stiles takes them, wipes them between Derek's ass cheeks and then wraps them around his cock so that it's completely sheathed in Stiles' come. Derek is so aroused by this that his hairy chest heaves and he's already fucking up into Stiles' grip.

Neither of them breaks eye contact as he uses Stiles' hand to get himself off. It's too much. The sight of his roommate all sweaty, combined with the knowledge that it's Stiles' come stopping the fabric of the boxers from chafing, is enough to have him reaching the peak of pleasure for a second time in under an hour. He hasn't been able to come twice in such quick succession since he was a horny teenager first discovering what his dick was for.

When it's done, Derek is trembling. Stiles leaves his boxers around Derek's cock and lies down beside him, petting him and murmuring sweet words in his ear.

"You did so good, Der," he says, kissing the tip of Derek's nose. "So damn good."

"Yeah?"

"Yeah. We're definitely doing this again."

Two orgasms in one night soon has Derek's eyelids drooping, reminding him that it was almost bedtime when Stiles had knocked on his door. "Tired…"

Stiles chuckles fondly. "I'll get a washcloth. Be right back, okay?"

"Mmhmm."

Derek drifts after Stiles' weight leaves the mattress. He can barely think, even when the weight returns and he feels Stiles wiping him down with the damp washcloth he'd retrieved from their shared bathroom down the hall. By the time that he's clean, Derek is close to falling asleep, and he finally slips under when Stiles pulls the sheets up over him, tucks him in and sweetly kisses his temple.

The last thing Derek hears is Stiles saying, "Sleep well, baby."

* * *

Just one month later, Stiles moves into Derek's bedroom and never leaves.

**Author's Note:**

> Well, this was a bit of a gross one, wasn't it? And yet, somehow, I was still turned on while writing it. XD This was also the 40th instalment in this kinky little series of mine. I never imagined when I started it that we'd reach this point, and I couldn't have were it not for you guys constantly keeping me inspired with your filthy ideas. Here's to 40 more! \o/ I'd like to say a huge thank you to 77thdegree for giving me this prompt. I hope it was everything you wanted it to be.
> 
> Stay tuned for my next PWP, a high school AU in which sweet and innocent omega!Stiles moves to a new school and catches the attention of alpha!Derek, a loner with very questionable morals. Top!Derek/bottom!Stiles.
> 
> **P.S. Don't forget to subscribe to me to be notified when my future fics go live, which will all be Sterek. And please check out my past fics if you haven't already and are interested.**


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